Simurgh, like Jo*mar said you have to work on your posture. Sounds like you may have a VTOS and it is a mechanical problem. I will suggest you to go take a look on my post about Re education posture global.I will think you have similar symptom than taybm20 with little differant way to get it. Go take a look on her or his post. I believe the R-P-G is the best way to go but i think a good PT or chiropractor who have good skills with TOS will be able to help you.

Alexis